National Forensic Doctor

24: Chapter 24 Starting from Scratch 24: Chapter 24 Starting from Scratch In the afternoon, after a bit of preparation, Jiang Yuan and Wang Zhong each rode their own electric scooters to the crime scene neighborhood.

Located in the suburbs, the red-brick buildings still carried a sense of the times, and the two-way four-lane road was lined with large trees of uncertain species on both sides and in the middle.

Sparse shrubbery proved that maintenance levels nearby were quite average, but the trees, planted with time, still maintained the basic quality of a residential area.

This was in the far suburbs of Ningtai County, but due to some nearby factories, it was more prosperous than many places within the county itself.

Of course, prosperous but not bustling.

As far as the eye could see, there were clusters of old residential complexes and new temporary buildings, keeping the environment on par with an old industrial area.

Small shops were the mainstream commercial model nearby, and the facades of these shops were mostly old-fashioned, hardly stimulating the desire to consume.

And these shops, too lazy to even tidy up their storefront curtains, similarly lacked the desire to install security cameras.

Municipal construction had come to a halt here as if frozen in time.

The old roads and traffic were still well-maintained, but probably only to the standards of the past, with almost no appearance of any new or improved infrastructure.

The crime scene’s complex appeared even more desolate compared to other complexes on the same road.

Only at the main entrance, were a few old men gathered, looking suspiciously at everything around them.

The complex’s other two main gates were now locked up with heavy chains.

What used to be measures for the convenience of residents were now considered the scapegoats.

“What are you doing?” Seeing Jiang Yuan and Wang Zhong trying to enter on their electric scooters, an old man bravely blocked the path with his body.

“Police,” they replied, having changed into plain clothes, and each showed their police badges for inspection.

The old man frowned, “I’ve heard that there are scammers who make fake police badges these days, are you swindlers…”

“If you don’t believe us, call 110,” Wang Zhong suggested, adding, “We are here to revisit the crime scene.

Would you like to be a witness?”

The old man had already taken out his phone ready to dial 110 but stopped, puzzled, “What?”

“We’re going to take a look at the scene, see if there’s any evidence left.

You just stand inside and watch; you’ll just need to sign something later,” Wang Zhong explained succinctly.

In China’s system for criminal case scene investigation, the investigating authority must invite a third-party individual to witness the inspection and examination activities at the crime scene.

This is different from the system often depicted in film and television from the United States.

The United States uses a self-authentication method for police officers, with mandated on-scene audio recording to ensure the fairness and standardization of the scene investigation.

By contrast, Japan and Russia also use a witness system for scene investigations, with varying differences.

Simply put, countries with witness systems require that every case’s evidence gathering is overseen by someone unrelated to the case, to minimize the occurrence of false evidence.

In countries like the United States, without a witness system, it is up to each police officer to self-regulate; if false evidence is presented, it could cast doubt on all cases handled by that officer.

Even though it wasn’t perfect in practice, as police officers, Jiang Yuan and Wang Zhong both adhered to the standards.

In fact, randomly picking one or two passersby didn’t quite align with the spirit of the crime scene investigation witness system.

Essentially, the system requires finding individuals with a certain understanding of the scene and of criminal investigation who are unrelated to the case to serve as witnesses, and the more often they can witness repeated examinations of the scene, the better.

However, in the current context where the public is uninformed, there are no economic compensations for witnesses, police officers are incredibly busy, and the judicial system’s standards are not very high, such requirements are clearly impractical.

Law enforcement would rather have cooperative, sensible witnesses who do not hinder the investigation or leak information.

The couple of old men, not yet retired but already living in retirement due to the decline of local enterprises, were quite suitable.

This was far more compliant than using auxiliary police as witnesses.

The few old men at the entrance might be idling away or possibly interested in the crime within the complex, and after a good period of questioning, they reluctantly watched as two seemingly young old men entered the building where the crime had occurred.

Wang Zhong, who had taken the keys from the office, casually lifted the police cordon, unlocked the door to enter, then locked it again after changing clothes.

The two old men, who were in fact retired due to age, were instructed to stand in the corner, not to speak, move, or take photos.

“Where do we start?” Wang Zhong hadn’t planned on coming; he didn’t have much confidence in conducting a reinvestigation, but since Jiang Yuan had ideas, he followed along.

Jiang Yuan looked around and said slowly, “Let’s start from the beginning.”

As he spoke, the system’s translucent interface unfolded:

Task: Start from the beginning.

Task details: Conduct a repeat examination of the Xue Ming case scene to obtain clues and evidence.

Jiang Yuan stared at the system interface for a few seconds, until it disappeared.

“Start from the beginning?” Wang Zhong was a bit perplexed by what he heard, then leaned closer to Jiang Yuan and whispered, “Is that necessary?”

“Let’s give it a try,” said Jiang Yuan as he set up the equipment and picked up a glass from the doorway shoe cabinet, dabbed a cotton swab with some water, and began to gently wipe it.

Despite having known each other for only a short time, and his own experience being slightly deeper, at heart, Wang Zhong respected Jiang Yuan.

Skills like fingerprinting show the disparity in ability all too clearly.

After standing idly for a moment, Jiang Yuan’s movements rendered Wang Zhong speechless.

Ordinary crime scene technicians in Ningtai County—or rather, when they wipe a glass—simply run a cotton swab around the rim.

This method, while possibly picking up DNA, has always been only a perfunctory practice.

Or rather, it’s a common practice for those lacking capability.

However, the way Jiang Yuan wiped glasses was something Wang Zhong had only seen on rare occasions.

Jiang Yuan would first dip the cotton swab in water, squeeze it to a semi-dry state, and while wiping, he wouldn’t move over a large area but choose a spot on the rim and rub the swab up and down, ensuring an even pressure as he wiped three to four times, aiming to pick up any potential DNA on the surface.

After finishing one spot, he would move a distance away and wipe another point repeatedly until he had completed the DNA extraction from the glass.

Such an approach naturally took much longer than sweeping around the rim, but the likelihood of extracting DNA was also much higher.

Wang Zhong had never tried Jiang Yuan’s method of swabbing for DNA, but from the various details of Jiang Yuan’s performance, Wang Zhong knew that Jiang Yuan’s skill level was indeed higher than that of the crime scene technicians in the team.

For instance, a semi-dry cotton swab is better at transferring DNA than a dry one, and also more effective than one saturated with water.

It’s about not being too dry or too wet.

To put it in terms Northerners would understand, think of the cotton swab as a bath scrubber: using a completely dry scrubber on dry skin won’t scrub away much dirt, nor will a fully wet one, since it just slides around.

You need a semi-dry scrubber for semi-dry skin to get the best effect and remove the most dirt.

For those not from the North, think of the cotton swab like a tongue: licking dry skin with a dry tongue won’t transfer much, nor will a soaking wet tongue work well.

You need a semi-dry tongue to lick semi-dry skin for the best effect and to achieve the optimal friction.

Similarly, Jiang Yuan’s method of wiping at a designated spot was much more effective than a sweeping motion around the rim.

To again use the Northerner’s understanding, it’s like scrubbing a specific spot with a bath scrubber versus using it in a sawing motion—the amount of dirt removed is incomparable.

And for non-Northerners, licking one spot is much more effective than randomly licking everywhere.

Since Jiang Yuan really had the know-how, Wang Zhong kept his questions to himself and simply followed Jiang Yuan’s lead, assisting him.

After several years at the criminal science team’s trace evidence position, Wang Zhong had long understood that some things may seem comprehensible when you see them, even quite understandable, but that doesn’t mean you can think of them on your own.

Coming up with an idea doesn’t mean you can apply it correctly, using it correctly doesn’t mean you can do it well, and doing it well doesn’t mean you can do it quickly.

To use an analogy that anyone who has gone through nine years of China compulsory education would understand: there are only five formulas in Euclidean geometry, only about a hundred words in Newton’s three laws; most people could understand them after a lesson, but when facing a problem, it’s not a given that they’ll know which formula to use.

Even if they figure it out, using it correctly is not guaranteed, nor is using it well or quickly.

Wang Zhong, who was used to investigating crime scenes, was caught off guard by how detailed, skillful, and swift Jiang Yuan was.

Fortunately, he had grown accustomed to assisting Jiang Yuan with fingerprints.

What was once awkward became smoother with practice, and as he worked, it even started to feel quite comfortable.